As a rule, plug-in pieces are used to join two housing parts in medium-sealed fashion, situated adjacent to one another, such as an engine block with adjacent aggregates. As a rule, they include of a tubular or sleeve-shaped support body made of a tough material that is equipped on its bilateral ends on the outer and/or inner circumference with annularly encircling sealing elements made of a rubber-elastic material. For connecting the housing parts, the plug-in pieces with their ends are inserted into corresponding boreholes of the housing parts or placed on corresponding tubular sleeves.
Upon inserting the ends of the sleeve-shaped support body into the particular boreholes of the housing parts or of a tubular sleeve, the sealing elements made of rubber-elastic material adjoin the plug-in piece on the inner walls of the boreholes or the outer wall of pipe sleeve and thus represent a medium-sealed connection between the two housing parts.
An example of a plug-in piece of the generic type is known from DE 195 48 249 A1. On its one end, the known plug-in piece exhibits a spherical sealing bead made of an elastomer. The spherically configured sealing bead also ensures a securely sealing adjoining on the inner surface of the borehole when the longitudinal axes of the boreholes and of the plug-in piece exhibit an angular offset to each other. Additionally, the inner surface of the borehole can roll away, when the connecting elements deflect out, with the seal of the connection ensured to remain tight. Due to the rolling away, there is a substantial reduction in the abrasion of the elastomer in comparison to a slippage or gliding due to the reduced frictional resistance.
What is a drawback with the known plug-in piece is that the circumferential compression of the sealing bead varies depending on the angular setting, due to which, with cardan-mounting, there can be varied erosion of the sealing bead on the curved sealing surface.